The present invention relates to fluid leak detection, and more particularly, to a hydrocarbon leak sensor for detection of fluid leakage from hydrocarbon fluid storage containers.
The detection and measurement of groundwater contaminants is of considerable interest. It is of particular interest to monitor the integrity of tanks containing potential environmental pollutants. For example, gasoline and oil tanks can cause severe contamination of the local environment, if such tanks leak.
Since it is usually impractical to conduct a manual or visual inspection of a buried storage tank, various remote sensing systems have been devised. For example, bore holes can be drilled and groundwater samples can be taken for off-site chemical analysis. However, sampling is time-consuming and expensive. Moreover, because physical sampling is only a periodic action, it is unlikely to be able to detect a leak or spill promptly and before significant damaged has occurred.
Various instruments for continuous monitoring of groundwater and the like have also been proposed, based on measurements, for example, of changes in dielectric properties or infrared spectral analysis of the contaminated fluids. However, these systems are typically very expensive and prone to maintenance problems.
It is therefore an object of the present invention to provide a sensor system capable of continuous monitoring for groundwater contamination.
It is another object of the present invention to provide an inexpensive, robust and compact sensor device which can be placed in a remote location, such as in a sump hole, in the drain pan under a fuel pump, or in the interstitial access between inner and outer walls of a double-walled storage tank, for detection of hydrocarbon fluid leakage.
Furthermore, it is preferable that in situ leakage sensor devices be inexpensive and be able to discriminate between groundwater and hydrocarbon fluids, and that the sensing be relatively unaffected by the amount of groundwater.
It is therefore another object of the present invention to provide an inexpensive and self-contained sensor device which can discriminate between groundwater and hydrocarbon fluid and can provide accurate measurements of hydrocarbon fluid at various levels of groundwater.